Estimation of hydraulic redistribution of Populus euphratica in Ebinur Lake Wetland Nature Reserve in Xinjiang Uygur Autonomous Region,China
新疆艾比湖湿地自然保护区胡杨根系水分再分配的估算

Aims Our objective was to construct and use a Ryel model to quantify hydraulic redistribution of Populus euphratica, a species in desert riparian vegetation. Methods We constructed a Ryel model to estimate the amount of net water redistribution under the canopy of P. euphratica. We based the model on data from studies measuring the shape and distribution of roots under the canopy of P. euphratica and observing values for volumetric water contents (θs), saturated hydraulic conductivity (Ks), maximum radial soil-root conductance of the entire active root system for water (CRT), soil water potential (ψi) and residual volumetric water contents (θr) in five soil layers. We used this model to make a short-term simulation of root hydraulic redistribution in different seasons. Important findings Hydraulic redistribution under the canopy of P. euphratica reached a maximum at 2:30 am. The amount of net water redistribution under the canopy decreased and moved towards the underlying soil with changes in the growing season. In June, hydraulic redistribution mainly occurred in the 0–40 cm soil layer, the maximum amount of redistribution was 0.022 0 cm and the total at night was up to 0.111 0 cm. In August, hydraulic redistribution mainly occurred in the 10–70 cm soil layer, the maximum amount of redistribution was 0.006 5 cm and the total at night was up to 0.018 4 cm. In October, hydraulic redistribution mainly occurred in the 70–100 cm soil layer, the maximum amount of redistribution was 0.003 9 cm and the total at night was up to 0.008 6 cm.